1. Technical Field
This invention relates to the field of computer speech recognition and more particularly to a method and system in which a speech recognition application can automatically determine whether a user implemented amendment to dictated text should serve as a basis to update a language model.
2. Description of the Related Art
Speech recognition is the process by which an acoustic signal received by microphone is converted to a set of words by a computer. These recognized words may then be used in a variety of computer software applications for purposes such as document preparation, data entry and command and control. Speech recognition is generally a difficult problem due to the wide variety pronunciations, individual accents and speech characteristics of individual speakers. Consequently, language models are often used to help reduce the search space of possible words and to resolve ambiguities as between similar sounding words. Such language models tend to be statistically based systems and can be provided in a variety of forms. The simplest language model can be specified as a finite state network, where the permissible words following each word are given explicitly. However, more sophisticated language models have also been developed which are specified in terms of a context specified grammar.
Since each particular user will tend to have their own style of speaking, it is important that the attributes of such speaking style be adapted to the language model. By continuously updating the language model, it is possible to improve the overall accuracy of the speech recognition process for that user and thereby permit greater efficiencies. Accordingly, it is desirable to update the language model for each particular user on a regular basis. This updating process may be accomplished by various means. For example, the speech recognition application may be provided with sample text in some instances as examples of a particular users' speaking style. This information may thereafter be used, if suitable, to update the language model. Another method for updating the language model involves making note of user"corrections" to misrecognized words in dictated text. However, this method can be cumbersome as it is necessary for the user to distinguish between amendments to text which are corrections to misrecognized words as compared to those which are merely additions or revisions to text. Corrections to misrecognized words are appropriately considered for updating the language model whereas other additions or revisions to text for other reasons are not necessarily so. The difficulty for the speech recognition application is distinguishing one type of amendment to the document from another.